4-Ammonio-5-meth­oxy-2-methyl­benzene­sulfonate

Kennedy, A.R.; Silva de Moraes, L.

doi:10.1107/S2414314616017788

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 11| November 2016| x161778

https://doi.org/10.1107/S2414314616017788

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4-Ammonio-5-methoxy-2-methylbenzenesulfonate

Alan R. Kennedy ^a ^* and Lygia Silva de Moraes ^a

^aWestChem, Department of Pure & Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland
^*Correspondence e-mail: a.r.kennedy@strath.ac.uk

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 3 November 2016; accepted 7 November 2016; online 8 November 2016)

The title compound, C₈H₁₁NO₄S, crystallizes as a zwitterion, with the negatively charged benzenesulfonate group and the positively charged NH₃⁺ group in mutually para positions. All the non-H atoms, except for one O atom of the sulfonate group, lie on a crystallographic mirror plane (Z′ = 1/2). In the crystal, the hydrogen-bonding structure is two-dimensional, propagating in the c-axis direction through a bifurcated hydrogen bond between the NH₃⁺ and the SO₃⁻ groups, and in the b-axis direction through an R₂²(16) ring motif involving the same functional groups. This latter hydrogen bonding is supported by offset π–π interactions [intercentroid distance = 3.8114 (4) Å].

Keywords: crystal structure; zwitterion; sulfonate; hydrogen bonding; offset π–π interactions.

CCDC reference: 1515425

Structure description

Amino-benzenesulfonic acids are used extensively in the preparation of azo dyes and pigments (Christie, 2015 ). Their crystal structures tend to be zwitterionic with a negatively charged sulfonate and protonation of the amine to give NH₃⁺ (Smith et al., 2006 ; Butcher & Deschamps, 2006 ; Śledź et al., 2010 ).

The title compound, crystallizes as a zwitterion, as shown in Fig. 1. The body of the molecule lies on the crystallographic mirror plane (Z′ = ½) with only atom O3 of the sulfonate group and H atoms of the methyl and NH₃⁺ groups out of plane. Close examination of the displacement ellipsoids of the methoxy group indicate that these are a little larger than those for the other atoms – thus there may be minor (unmodelled) out of plane disorder present.

Figure 1
The molecular structure of the title compound, showing the atom labelling and displacement ellipsoids drawn at the 50% probability level [symmetry code: (v) x, −y + $[{1\over 2}]$ , z].

In the crystal, hydrogen bonding involves the NH₃⁺ group as an H-donor and the O atoms of the SO₃⁻ group as the acceptors (Table 1). This gives a two-dimensional hydrogen-bonding network (Fig. 2), with bifurcated bonds from H atom H2N to O3ⁱⁱ and O3ⁱⁱⁱ (see Table 1), forming sheets parallel to the ab plane, and the remaining donor and acceptor atoms forming an R₂²(16) ring motif that supports offset π–π stacking parallel to the b-axis direction (Table 1 and Fig. 3); intercentroid distances Cg⋯Cg^a,b,c = 3.8114 (4) Å, Cg is the centroid of the benzene ring C1–C6, interplanar distances = 3.4705 Å, slippages = 1.575 Å, symmetry codes: (a) −x + 1, −y, −z + 1, (b) −x + 1, y − $[{1\over 2}]$ , −z + 1, (c) −x + 1, y + $[{1\over 2}]$ , −z + 1.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O3ⁱ	0.89 (2)	1.83 (2)	2.7100 (13)	171.9 (16)
N1—H2N⋯O3ⁱⁱ	0.89 (3)	2.35 (3)	3.0909 (18)	141 (1)
N1—H2N⋯O3ⁱⁱⁱ	0.89 (3)	2.35 (3)	3.0909 (18)	141 (1)
Symmetry codes: (i) -x+1, -y, -z+1; (ii) x, y, z-1; (iii) $[x, -y+{\script{1\over 2}}, z-1]$ .

Figure 2
A view along the a axis of the crystal packing of the title compound. Hydrogen bonds are drawn as dashed lines (see Table 1

) and only the ammonium H atoms have been included.

Figure 3
The R₂²(16) ring motif, with hydrogen bonds drawn as dashed lines (see Table 1

), that supports π–π stacking parallel to the b-axis direction.

Synthesis and crystallization

The crystallization of 4-azaniumyl-5-methoxy-2-methylbenzene-1-sulfonate occurred during an attempt to synthesize a salt form of rac-methylephedrine by reaction with 4-amino-5-methoxy-2-methylbenzenesulfonic acid (Kennedy et al., 2011 ). Synthesis was by adding 1.10 mmol of the acid to 1.00 mmol of the base, both previously partially dissolved in approximately 5 ml of deionized water. The resulting solution was stirred for 30 min at 323 K, filtered into a test tube and left to slowly evaporate. The title compound crystallized as colourless plates on the walls of the test tube.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	NH₄⁺·C₈H₇O₄S⁻
M_r	217.24
Crystal system, space group	Monoclinic, P2₁/m
Temperature (K)	123
a, b, c (Å)	8.0644 (3), 6.9410 (2), 8.6192 (3)
β (°)	105.039 (4)
V (Å³)	465.94 (3)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.34
Crystal size (mm)	0.34 × 0.19 × 0.08

Data collection
Diffractometer	Oxford Diffraction Xcalibur E
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2014 )
T_min, T_max	0.960, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	4897, 1187, 1101
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.680

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.081, 1.10
No. of reflections	1187
No. of parameters	103
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.34, −0.46
Computer programs: CrysAlis PRO (Agilent, 2014), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ) and Mercury (Macrae et al., 2008 ).

Structural data

CCDC reference: 1515425

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314616017788/su4094sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616017788/su4094Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314616017788/su4094Isup3.cml

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

4-Azaniumyl-5-methoxy-2-methylbenzenesulfonate top

Crystal data top

NH₄⁺·C₈H₇O₄S⁻	F(000) = 228
M_r = 217.24	D_x = 1.548 Mg m⁻³
Monoclinic, P2₁/m	Mo Kα radiation, λ = 0.71073 Å
a = 8.0644 (3) Å	Cell parameters from 3052 reflections
b = 6.9410 (2) Å	θ = 3.8–28.4°
c = 8.6192 (3) Å	µ = 0.34 mm⁻¹
β = 105.039 (4)°	T = 123 K
V = 465.94 (3) Å³	Plate, colourless
Z = 2	0.34 × 0.19 × 0.08 mm

Data collection top

Oxford Diffraction Xcalibur E diffractometer	1101 reflections with I > 2σ(I)
Radiation source: sealed tube	R_int = 0.017
ω scans	θ_max = 28.9°, θ_min = 3.1°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	h = −10→10
T_min = 0.960, T_max = 1.000	k = −9→8
4897 measured reflections	l = −11→11
1187 independent reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.029	Hydrogen site location: mixed
wR(F²) = 0.081	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ²(F_o²) + (0.0421P)² + 0.2128P] where P = (F_o² + 2F_c²)/3
1187 reflections	(Δ/σ)_max < 0.001
103 parameters	Δρ_max = 0.34 e Å⁻³
0 restraints	Δρ_min = −0.46 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.3390 (2)	0.2500	0.5975 (2)	0.0141 (3)
C2	0.2229 (2)	0.2500	0.4465 (2)	0.0153 (4)
H2	0.1029	0.2500	0.4370	0.018*
C3	0.2838 (2)	0.2500	0.3100 (2)	0.0145 (3)
C4	0.4604 (2)	0.2500	0.3286 (2)	0.0136 (3)
C5	0.5753 (2)	0.2500	0.4784 (2)	0.0143 (3)
H5	0.6951	0.2500	0.4868	0.017*
C6	0.5174 (2)	0.2500	0.6183 (2)	0.0139 (3)
C8	0.6490 (2)	0.2500	0.7788 (2)	0.0179 (4)
N1	0.5211 (2)	0.2500	0.18268 (18)	0.0160 (3)
O1	0.18687 (16)	0.2500	0.15613 (15)	0.0203 (3)
O2	0.06437 (18)	0.2500	0.70299 (17)	0.0283 (4)
O3	0.31405 (13)	0.07835 (14)	0.85950 (11)	0.0242 (3)
S1	0.24756 (5)	0.2500	0.76544 (5)	0.01480 (15)
C7	0.0052 (3)	0.2500	0.1290 (3)	0.0410 (7)
H1N	0.583 (2)	0.146 (2)	0.1771 (19)	0.023 (4)*
H2N	0.430 (4)	0.2500	0.097 (3)	0.037 (7)*
H8B	0.642 (2)	0.140 (3)	0.844 (2)	0.033 (5)*
H7B	−0.033 (3)	0.136 (3)	0.178 (3)	0.053 (6)*
H7A	−0.036 (4)	0.2500	0.022 (4)	0.056 (9)*
H8A	0.762 (4)	0.2500	0.763 (3)	0.043 (8)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0145 (8)	0.0160 (8)	0.0127 (8)	0.000	0.0055 (6)	0.000
C2	0.0126 (8)	0.0195 (9)	0.0142 (8)	0.000	0.0041 (6)	0.000
C3	0.0145 (8)	0.0164 (8)	0.0116 (8)	0.000	0.0017 (6)	0.000
C4	0.0163 (8)	0.0146 (8)	0.0116 (8)	0.000	0.0066 (6)	0.000
C5	0.0118 (8)	0.0163 (8)	0.0149 (8)	0.000	0.0038 (6)	0.000
C6	0.0140 (8)	0.0153 (8)	0.0123 (8)	0.000	0.0033 (6)	0.000
C8	0.0142 (9)	0.0258 (10)	0.0127 (8)	0.000	0.0018 (6)	0.000
N1	0.0156 (8)	0.0219 (8)	0.0117 (7)	0.000	0.0059 (6)	0.000
O1	0.0149 (7)	0.0344 (8)	0.0105 (6)	0.000	0.0010 (5)	0.000
O2	0.0150 (7)	0.0522 (10)	0.0195 (7)	0.000	0.0077 (5)	0.000
O3	0.0332 (6)	0.0241 (5)	0.0201 (5)	0.0068 (4)	0.0156 (4)	0.0057 (4)
S1	0.0150 (2)	0.0192 (2)	0.0118 (2)	0.000	0.00628 (16)	0.000
C7	0.0151 (10)	0.088 (2)	0.0167 (10)	0.000	−0.0021 (8)	0.000

Geometric parameters (Å, º) top

C1—C2	1.392 (2)	C6—C8	1.510 (2)
C1—C6	1.403 (2)	C8—H8B	0.960 (18)
C1—S1	1.7869 (17)	C8—H8A	0.96 (3)
C2—C3	1.388 (2)	N1—H1N	0.886 (18)
C2—H2	0.9500	N1—H2N	0.89 (3)
C3—O1	1.354 (2)	O1—C7	1.422 (3)
C3—C4	1.391 (2)	O2—S1	1.4351 (14)
C4—C5	1.380 (2)	O3—S1	1.4625 (10)
C4—N1	1.464 (2)	S1—O3ⁱ	1.4624 (10)
C5—C6	1.401 (2)	C7—H7B	0.99 (2)
C5—H5	0.9500	C7—H7A	0.90 (4)

C2—C1—C6	122.56 (15)	C1—C6—C8	124.83 (15)
C2—C1—S1	116.02 (13)	C6—C8—H8B	113.8 (11)
C6—C1—S1	121.42 (13)	C6—C8—H8A	109.9 (17)
C3—C2—C1	119.50 (16)	H8B—C8—H8A	106.4 (14)
C3—C2—H2	120.2	C4—N1—H1N	111.3 (11)
C1—C2—H2	120.2	C4—N1—H2N	108.6 (18)
O1—C3—C2	126.10 (16)	H1N—N1—H2N	108.0 (14)
O1—C3—C4	115.26 (15)	C3—O1—C7	118.00 (15)
C2—C3—C4	118.64 (16)	O2—S1—O3ⁱ	113.68 (5)
C5—C4—C3	121.77 (15)	O2—S1—O3	113.68 (5)
C5—C4—N1	120.73 (15)	O3ⁱ—S1—O3	109.11 (8)
C3—C4—N1	117.49 (15)	O2—S1—C1	107.28 (8)
C4—C5—C6	120.80 (16)	O3ⁱ—S1—C1	106.27 (5)
C4—C5—H5	119.6	O3—S1—C1	106.27 (5)
C6—C5—H5	119.6	O1—C7—H7B	110.8 (13)
C5—C6—C1	116.72 (15)	O1—C7—H7A	105 (2)
C5—C6—C8	118.44 (15)	H7B—C7—H7A	111.6 (17)

C6—C1—C2—C3	0.000 (1)	C2—C1—C6—C5	0.000 (1)
S1—C1—C2—C3	180.000 (1)	S1—C1—C6—C5	180.000 (1)
C1—C2—C3—O1	180.000 (1)	C2—C1—C6—C8	180.000 (1)
C1—C2—C3—C4	0.000 (1)	S1—C1—C6—C8	0.000 (1)
O1—C3—C4—C5	180.000 (1)	C2—C3—O1—C7	0.000 (1)
C2—C3—C4—C5	0.000 (1)	C4—C3—O1—C7	180.000 (1)
O1—C3—C4—N1	0.000 (1)	C2—C1—S1—O2	0.000 (1)
C2—C3—C4—N1	180.000 (1)	C6—C1—S1—O2	180.000 (1)
C3—C4—C5—C6	0.000 (1)	C2—C1—S1—O3ⁱ	−121.93 (5)
N1—C4—C5—C6	180.000 (1)	C6—C1—S1—O3ⁱ	58.07 (5)
C4—C5—C6—C1	0.000 (1)	C2—C1—S1—O3	121.93 (5)
C4—C5—C6—C8	180.000 (1)	C6—C1—S1—O3	−58.07 (5)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O3ⁱⁱ	0.89 (2)	1.83 (2)	2.7100 (13)	171.9 (16)
N1—H2N···O3ⁱⁱⁱ	0.89 (3)	2.35 (3)	3.0909 (18)	141 (1)
N1—H2N···O3^iv	0.89 (3)	2.35 (3)	3.0909 (18)	141 (1)

Symmetry codes: (ii) −x+1, −y, −z+1; (iii) x, y, z−1; (iv) x, −y+1/2, z−1.

Acknowledgements

The financial support of a PhD studentship by CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico) and the support of GSK is gratefully acknowledged.

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